IEC 61000-4-34: Testing and Measurement Techniques - Voltage Dips, Short Interruptions...

IEC 61000-4-34 defines the immunity test methods and range of preferred test levels for electrical and electronic equipment connected to low-voltage power supply networks for voltage dips, short interruptions, and voltage variations.

This standard applies to electrical and electronic equipment having a rated input current exceeding 16 A per phase, for connection to 50 Hz or 60 Hz A.C. networks.

It does not apply to electrical and electronic equipment for connection to 400 Hz A.C. networks. Tests for these networks will be covered by future IEC standards.

The object of this standard is to establish a common reference for evaluating the immunity of electrical and electronic equipment when subjected to voltage dips, short interruptions and voltage variations.

This second edition cancels and replaces the first edition published in 1994 and its amendment 1 (2000). This second edition constitutes a technical revision in which:

• Preferred test values and durations have been added for the different environment classes.
• Tests for the three-phase systems have been specified.

It has the status of a Basic EMC Publication in accordance with IEC Guide 107.
 

Dips and Interrupts Background

Dips and interrupts can occur on AC power mains as a result of a fault in the distribution system such as an open circuit breaker or a sudden large load being turned on in the immediate vicinity. A power distribution system fault can cause a switch in the distribution grid to open and close a number of times, resulting in multiple interrupts to electrical and electronic equipment.

Electronic products are tested for immunity to dips and interrupts to insure their continued reliable operation if subjected to dips and/or interrupts on the AC power mains. The European Union’s EMC Directive mandates dips and interrupts testing for virtually all electrical and electronic products as a condition for obtaining the CE Mark before shipping products to member states of the European Union.
 

Applicable Standards

Generic Immunity Standards, Product Standards, and Product Family Standards require that dip and interrupt tests be performed in accordance with Basic EMC Standards: IEC 61000-4-34 and EN 61000-4-34. Thermo KeyTek’s Application Note, “EMC Standards Overview,” provides an overview of European Standards for electromagnetic compatibility, describes how the Standards relate to one another, and lists sources for procuring copyrighted documents.

IEC 61000-4-34 and EN 61000-4-34 are virtually identical standards.
 

Basic EMC Standard

The Basic EMC Standard for Dips and Interrupts defines methods of generating consistently reproducible electrical dips and interrupts for test purposes. They specify characteristics of the AC mains to the EUT such as peak inrush current, transition times, and durations. While the Basic EMC Standard specifies how to perform Dips and Interrupts testing, the Generic, Product, and Product Family Standards specify the test levels and pass/fail Performance Criteria.
 

Test Levels

Standard	Applicability	Levels
EN 50082-1	Generic Immunity – Residential, Commercial and Light Industrial	Not required
EN 50082-1 Draft	Generic Immunity – Residential, Commercial and Light Industrial	0%, 40%, 70% & 100%
EN 50082-2	Generic Immunity – Industrial Environment	Not required
EN 50082-2 Draft	Generic Immunity – Industrial Environment	0%, 40%, 70% & 100%
EN 55104	Immunity for Household Appliances, Tools and Similar Apparatus	0%, 40%, 70% & 100%

Peak Inrush Current

IEC 61000-4-34 requires the simulator be capable of supplying peak inrush currents of up to 500A for 220V to 240V mains, and up to 250A for 100V to 120V mains. Additionally, the Standard requires this capability be measured using a bridge rectifier connected via a switch to a discharged 1700µF capacitor. The parallel discharge resistance should be chosen to allow several RC time constants between tests. An example in Annex A (normative) uses a 10k ohm resistance, providing a time constant of 17s, "...so that a wait of 1.5 to 2 minutes should be used between inrush drive capability tests."

The test for inrush current is performed by switching the generator from 0% to 100% at both 90Þ and 270Þ to insure sufficient peak inrush current drive capability for both polarities.
 

Waveform Verification

IEC 61000-4-34 requires that the simulator output be verified periodically. For dip and interrupt test simulators, it is necessary to verify the voltage transition levels, transition times to 100%, and the inrush current capability. Most modern oscilloscopes are capable of observing the voltage levels and transition times. For verifying the inrush current, a bridge rectifier, suitably rated 1700µF capacitor, and appropriate current transformer are required.

Rise and fall times of PQF™ simulator transitions



 

Test Execution

According to IEC 61000-4-34, tests must be performed in compliance with the manufacturer's test plan, which shall specify:
• Input power of the EUT
• Performance criteria
• Operation modes of the EUT
• Test set-up description
• Type of designation of the EUT
• Information on possible connections, cables, peripherals, etc. After each group of tests, a complete functional test must be performed.
 

EUT Performance Criteria

For dip and interrupt tests, performance criteria varies in some standards depending on the duration or severity of the dip and/or interrupt. Under some conditions, loss of function is allowed, provided that the function is self-recoverable or can be restored by the control operations. Under less severe conditions, degradation of performance is allowed during the test, however, the unit must continue to operate as intended after the test. Refer to the tables located in the Generic, Product, and Product Family Standards for specific Performance Criteria. The product cannot become unsafe under any conditions.